Most speed changers in use today utilize gears to produce an output speed different than the input speed. Gears require the manufacture of precise shapes for the teeth to satisfy the fundamental law of gearing which insures a constant speed ratio for the system. If the gears are to be used in a transmission, special provision must be made so the speed ratio can be changed without causing gear teeth on one gear to clash with those on the mating gear.
There are, however, other types of speed changers in use including traction drive speed changers. These depend on friction between rolling elements to transmit torque from the input member to the output member. The rolling elements are held together with a prescribed normal force to generate the required friction force based on the power to be transmitted by the device. However, these devices are not self-actuating. Further, these devices often require a separate clutch to allow the output to be disengaged from the input.
It is therefore a principal object of this invention to provide a traction drive speed changer which is self-actuating.
It is a further object of this invention to provide a traction drive speed reducer that does not require a clutch.
A further object of this invention is to provide a self-actuating traction drive speed changer wherein the normal force on the roller members is only present when needed to permit the rolling elements to be operationally disengaged.
A still further object of this invention is to provide a self-actuating traction drive speed changer which can be easily engaged and disengaged in response to changing speed requirements.
These and other objects will be apparent to those skilled in the art.